以Al2O3为过渡层脉冲激光法制备PZT铁电薄膜

Growth of high quality PZT thin film with Al2O3 buffer layer by pulsed laser deposition

  • 摘要: 为实现PZT铁电薄膜与半导体衬底的直接集成引入Al2O3为过渡层,首先用真空电子束蒸发法在Si(100)、多晶金刚石(111)衬底上生长约20nm厚的Al2O3过渡层,接着在上述衬底上采用脉冲激光淀积(PLD)法淀积PZT薄膜,衬底温度为350-550℃。X光电子能谱(XPS)测试表明,在高真空下,电子束蒸发Al2O3固态源能获得化学配比接近蒸发源的Al2O3薄膜。X射线衍射(XRD)测试说明,不论衬底是硅还是多晶金刚石,当衬底温度为550℃时,PZT在Al2O3过渡层上呈现(222)取向的焦绿石相结构。当衬底是金刚石时,通过如下工艺:(1)较低温度(350℃)淀积;(2)空气氛围650℃快速退火5min,可以在Al2O3过渡层上获得高度(101)取向的钙钛矿结构的铁电相PZT薄膜。最后AFM测试显示,在硅衬底上,PZT薄膜的表面均方根粗糙度为9.78nm;而在多晶金刚石衬底上,PZT薄膜的表面均方根粗糙度为17.2nm。

     

    Abstract: In order to realize the integration of ferroelectric thin film and semiconductor substrate,Al2O3 was used as buffer layer.First,Al2O3 buffer layer was grown on Si(100),polycrystalline diamond(111)substrates with the thickness about 20nm by vacuum electron-beam evaporation method,then lead zirconate titanate(PZT)thin film was deposited on these substrates by pulsed laser deposition(PLD).XPS results suggest that at high vacuum ambient,stoichiometric Al2O3 thin film can be obtained by the method of electron-beam vaporizing solid-state Al2O3 source.XRD results show that when the temperature is 550℃,pyrochlore PZT film with(222)orientation can be obtained on both substrates,and when substrate is diamond,highly preferential(101)orientation perovskite PZT can be prepared by the processes:(1)low-temperature(350℃)deposition;(2)650℃ annealing for 5 min in air ambient.AFM images show that the mean roughness of the PZT film is 9.8nm on silicon,and 17.2nm on diamond respectively.

     

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